#include "debug.h"
/*!
 * \file MD5.cpp
 * \brief C++ implementation of MD5 Message-Digest Algorithm as describe in
 *   RFC1321.
 *
 * Written by Ulrich Drepper <drepper@gnu.ai.mit.edu> and heavily modified 
 *   for GnuPG by <werner.koch@guug.de> and adapted for the need of FPM Blowfish 
 *   Plugin
 *
 * \author Frederic RUAUDEL <grumz@users.sf.net>
 *
 * $Revision: 1.1 $
 * $Date: 2003/03/07 10:54:38 $
 *
 * \b FPMBlowfishPlugin
 * Copyleft (c) 2003 Frederic RUAUDEL, all rights reversed
 *
 * Copyleft (C) 1995, 1996, 1998, 1999 Free Software Foundation, Inc.
 *
 * This program is free software which I release under the GNU General Public
 * License. You may redistribute and/or modify this program under the terms
 * of that license as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.  Version 2 is in the
 * COPYING file in the top level directory of this distribution.
 *
 * To get a copy of the GNU General Public License, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 **/

#include "md5.h"

MD5::MD5 ()
{
	this->init ();
}

MD5::~MD5 () 
{
#ifdef DEBUG
	cerr << "Destroying MD5...OK" << endl;
#endif
}

/****************
 * FPM: At this point I diverge from GnuPG's implementation to write my
 * own wrapper function.  I'll use this to hash the passphrase.
 */

byte* MD5::hash (byte *buf, size_t nbytes)
{
	byte* ret_val;
  
	this->init ();
#ifdef DEBUG
	cerr << "First write (nbytes = " << nbytes << ")" << endl;
#endif
	this->write (buf, nbytes);
#ifdef DEBUG
	cerr << "Final" << endl;
#endif
	this->final ();

#ifdef DEBUG
	cerr << "End" << endl;
#endif
	ret_val = (byte*)malloc (16);
	memset (ret_val, 0, 16);
	memcpy(ret_val, this->read (), 16);

	return (ret_val);
}
  
void MD5::print (byte* key, size_t nbytes, byte* hash)
{
	int i;
	
	printf ("%.*s", nbytes, (char*)key);
	for (i = 0; i < 16; i++)
	{
		printf (" %02X", hash[i]);
		if (i == 7)
		{
			printf (" ");
		}
	}
	printf ("\n");
}

void MD5::init (void)
{
    this->A = 0x67452301;
    this->B = 0xefcdab89;
    this->C = 0x98badcfe;
    this->D = 0x10325476;

    this->nblocks = 0;
    this->count = 0;
}

/****************
 * transform n*64 bytes
 */
void MD5::transform(byte *data )
{
    u32 correct_words[16];
    u32 A = this->A;
    u32 B = this->B;
    u32 C = this->C;
    u32 D = this->D;
    u32 *cwp = correct_words;

#ifdef BIG_ENDIAN_HOST
	{ 
		int i;
		byte *p2, *p1;
		
		for (i = 0, p1 = data, p2 = (byte*)correct_words; i < 16; i++, p2 += 4) 
		{
			p2[3] = *p1++;
			p2[2] = *p1++;
			p2[1] = *p1++;
			p2[0] = *p1++;
		}
	}
#else
    memcpy (correct_words, data, 64);
#endif


#define OP(a, b, c, d, s, T)					    \
	do								    \
    {								    \
		a += FF (b, c, d) + (*cwp++) + T; 	    \
		a = rol(a, s);						    \
		a += b;							    \
    } while (0)

    /* Before we start, one word about the strange constants.
       They are defined in RFC 1321 as

       T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
     */

    /* Round 1.  */
    OP (A, B, C, D,  7, 0xd76aa478);
    OP (D, A, B, C, 12, 0xe8c7b756);
    OP (C, D, A, B, 17, 0x242070db);
    OP (B, C, D, A, 22, 0xc1bdceee);
    OP (A, B, C, D,  7, 0xf57c0faf);
    OP (D, A, B, C, 12, 0x4787c62a);
    OP (C, D, A, B, 17, 0xa8304613);
    OP (B, C, D, A, 22, 0xfd469501);
    OP (A, B, C, D,  7, 0x698098d8);
    OP (D, A, B, C, 12, 0x8b44f7af);
    OP (C, D, A, B, 17, 0xffff5bb1);
    OP (B, C, D, A, 22, 0x895cd7be);
    OP (A, B, C, D,  7, 0x6b901122);
    OP (D, A, B, C, 12, 0xfd987193);
    OP (C, D, A, B, 17, 0xa679438e);
    OP (B, C, D, A, 22, 0x49b40821);

#undef OP
#define OP(f, a, b, c, d, k, s, T)  \
	do								      \
	{ 							      \
		a += f (b, c, d) + correct_words[k] + T;		      \
		a = rol(a, s);						      \
		a += b; 						      \
	} while (0)

    /* Round 2.  */
    OP (FG, A, B, C, D,  1,  5, 0xf61e2562);
    OP (FG, D, A, B, C,  6,  9, 0xc040b340);
    OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
    OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
    OP (FG, A, B, C, D,  5,  5, 0xd62f105d);
    OP (FG, D, A, B, C, 10,  9, 0x02441453);
    OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
    OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
    OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);
    OP (FG, D, A, B, C, 14,  9, 0xc33707d6);
    OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);
    OP (FG, B, C, D, A,  8, 20, 0x455a14ed);
    OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);
    OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);
    OP (FG, C, D, A, B,  7, 14, 0x676f02d9);
    OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);

    /* Round 3.  */
    OP (FH, A, B, C, D,  5,  4, 0xfffa3942);
    OP (FH, D, A, B, C,  8, 11, 0x8771f681);
    OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
    OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
    OP (FH, A, B, C, D,  1,  4, 0xa4beea44);
    OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);
    OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);
    OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
    OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);
    OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);
    OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);
    OP (FH, B, C, D, A,  6, 23, 0x04881d05);
    OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);
    OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
    OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
    OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);

    /* Round 4.  */
    OP (FI, A, B, C, D,  0,  6, 0xf4292244);
    OP (FI, D, A, B, C,  7, 10, 0x432aff97);
    OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
    OP (FI, B, C, D, A,  5, 21, 0xfc93a039);
    OP (FI, A, B, C, D, 12,  6, 0x655b59c3);
    OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);
    OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
    OP (FI, B, C, D, A,  1, 21, 0x85845dd1);
    OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);
    OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
    OP (FI, C, D, A, B,  6, 15, 0xa3014314);
    OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
    OP (FI, A, B, C, D,  4,  6, 0xf7537e82);
    OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
    OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
    OP (FI, B, C, D, A,  9, 21, 0xeb86d391);

    /* Put checksum in context given as argument.  */
    this->A += A;
    this->B += B;
    this->C += C;
    this->D += D;
}

/* The routine updates the message-digest context to
 * account for the presence of each of the characters inBuf[0..inLen-1]
 * in the message whose digest is being computed.
 */
void MD5::write(byte *inbuf, size_t inlen)
{
    if (this->count == 64) /* flush the buffer */
	{
#ifdef DEBUG
		cerr << "flush buffer 1 (count= " << this->count << ")" << endl;
#endif
		this->transform (this->buf);
		this->count = 0;
		this->nblocks++;
    }

    if (!inbuf)
	{
		return;
	}
	
    if (this->count) 
	{
		for( ; inlen && this->count < 64; inlen-- )
		{
#ifdef DEBUG
			cerr << "1st loop (count= " << this->count << ")" << endl;
#endif
	    	this->buf[this->count++] = *inbuf++;
		}
	
		this->write (NULL, 0);
		if( !inlen )
		{
			return;
		}
    }

    while( inlen >= 64 ) 
	{
#ifdef DEBUG
		cerr << "flush buffer 2 (count= " << this->count << ")" << endl;
#endif
		this->transform (inbuf);
		this->count = 0;
		this->nblocks++;
		inlen -= 64;
		inbuf += 64;
    }

    for( ; inlen && this->count < 64; inlen-- )
	{
#ifdef DEBUG
		cerr << "2nd loop (count= " << this->count << ")" << endl;
#endif
		this->buf[this->count++] = *inbuf++;
	}
}


/* The routine final terminates the message-digest computation and
 * ends with the desired message digest in mdContext->digest[0...15].
 * The handle is prepared for a new MD5 cycle.
 * Returns 16 bytes representing the digest.
 */

void MD5::final(void)
{
    u32 t, msb, lsb;
    byte *p;

    this->write (NULL, 0); /* flush */;

    msb = 0;
    t = this->nblocks;

    if ((lsb = t << 6) < t) /* multiply by 64 to make a byte count */
	{
		msb++;
	}
	
    msb += t >> 26;
    t = lsb;
	
    if ((lsb = t + this->count) < t) /* add the count */
	{
		msb++;
	}
	
    t = lsb;
    
	if ((lsb = t << 3) < t) /* multiply by 8 to make a bit count */
	{
		msb++;
	}

    msb += t >> 29;

    if (this->count < 56) /* enough room */
	{
		this->buf[this->count++] = 0x80; /* pad */

		while (this->count < 56)
		{
			this->buf[this->count++] = 0;  /* pad */
		}
    }
    else /* need one extra block */
	{
		this->buf[this->count++] = 0x80; /* pad character */

		while (this->count < 64)
		{
			this->buf[this->count++] = 0;
		}
		
		this->write (NULL, 0);  /* flush */;
		
		memset(this->buf, 0, 56); /* fill next block with zeroes */
    }
	
    /* append the 64 bit count */
    this->buf[56] = lsb	   ;
    this->buf[57] = lsb >>  8;
    this->buf[58] = lsb >> 16;
    this->buf[59] = lsb >> 24;
    this->buf[60] = msb	   ;
    this->buf[61] = msb >>  8;
    this->buf[62] = msb >> 16;
    this->buf[63] = msb >> 24;
	
    this->transform(this->buf);

    p = this->buf;
	
#ifdef BIG_ENDIAN_HOST
	#define X(a) do { *p++ = this->##a	  ; *p++ = this->##a >> 8;      \
		      *p++ = this->##a >> 16; *p++ = this->##a >> 24; } while(0)
#else /* little endian */
    /*#define X(a) do { *(u32*)p = this->##a ; p += 4; } while(0)*/
    /* Unixware's cpp doesn't like the above construct so we do it his way:
     * (reported by Allan Clark) */
    #define X(a) do { *(u32*)p = (*this).a ; p += 4; } while(0)
#endif
				  
    X(A);
    X(B);
    X(C);
    X(D);
	
#undef X
}

byte* MD5::read (void)
{
    return this->buf;
}

